FAIR VALUE - Assets and Liabilities Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Level 3) (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2017	Dec. 31, 2016
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Discount rate used for calculation of mortgage servicing rights value		14.20%	14.10%
Fair value input prepayment rate		16.50%	13.80%
Private Label Mbs [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value	$ 17,630	$ 17,630
Discount rate used for calculation of mortgage servicing rights value	14.20%
Private Label Mbs [Member] | Discounted Cash Flow [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Valuation technique		Discounted cash flow
US States And Political Subdivisions Member [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value	$ 2,609	$ 2,609
Discount rate used for calculation of mortgage servicing rights value	0.07%
Unobservable input prepayment rate	3.00%	3.00%
US States And Political Subdivisions Member [Member] | Discounted Cash Flow [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Valuation technique		Discounted cash flow
Minimum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Discount rate used for calculation of mortgage servicing rights value			12.88%
Fair value input prepayment rate		12.00%	6.50%
Minimum [Member] | Private Label Mbs [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable input prepayment rate	12.00%	12.00%
Fair value projected Cumulative Loss Rate	0.10%	0.10%
Maximum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Discount rate used for calculation of mortgage servicing rights value			14.43%
Fair value input prepayment rate		29.00%	22.50%
Maximum [Member] | Private Label Mbs [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable input prepayment rate	29.90%	29.90%
Fair value projected Cumulative Loss Rate	7.10%	7.10%
Weighted Average [Member] | Private Label Mbs [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value input prepayment rate	16.50%
Unobservable input projected cumulative loss rate	4.00%	4.00%